Encountering a novel controlled-substance analog (designer drug) has become a distinct possibility for all forensic drug laboratories. 3,4-Methylenedioxyamphetamine (MDA) in particular is a receptive parent compound for the molecular modifications which produce such homologs and analogs. The identification of these compounds, however, can prove to be an arduous task. It would be desirable to direct the focus of the identification to those compounds which are the more likely candidates for clandestine-laboratory synthesis. The process of narrowing the range of theoretical possibilities to logical choices may be enhanced by using a suitable predictive scheme. Such a predictive scheme for MDA analogs is presented based on putative Central Nervous System activity, existence or formulation of a reasonable synthesis method, and availability of the required precursors.